truncating a file from the top down

Fredrik Lundh fredrik at pythonware.com
Tue Mar 29 19:29:20 CEST 2005


Mike Rovner wrote:

> if os.stat says the_file is too big:
>   fh = open(the_file, 'rb')
>   fh.seek(2008, 2)

should be

    fh.seek(-2008, 2)

right?

>   data = fh.read()
>   fh.close()
>   assert len(data)==2008 # you may want some error processing here
>   fh = open(the_file, 'wb')
>   fh.write(data)
>   fh.close()

or

    if os.path.getsize(the_file) > TOO_BIG:
        fh = open(the_file, 'rb+')
        fh.seek(-2008, 2)
        data = fh.read()
        fh.seek(0) # rewind
        fh.write(data)
        fh.truncate()
        fh.close()

</F> 






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